At that mileage it could be either (or both). Pull the intercooler and drain any oil present. Wash it out with kerosene and clean out the intake piping. Check in a week to see how much oil has accumulated and watch to see if the amount of smoke when coming off throttle is reduced. Valve seals usually give themselves away long before they're this bad by smoking when cold and then stopping when warm.
If you have a vacuum gauge you can test it as shown in the following link:
http://www.cygnusx1.net/supra/TechTi..._readings.aspx